JP2002324305A - Method to produce magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to produce a magnetic head which reproduces magnified information for recording medium, utilizing the change of impedance by outside magnetic fields. SOLUTION: In the method to produce magnetic head, there are formed a first soft magnetic layer, conductor wire/coil, a second soft magnetic film and dielectric film with each prescript shapes in order, by sputtering and ion- milling processing, on an insulated substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a magnetic head for reading and reproducing information from a magnetic storage medium in which information relating to video, audio, characters and the like is recorded in the direction and strength of magnetization.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for information storage devices of higher recording density and smaller size and larger capacity. As the storage capacity of the storage device becomes larger, higher speeds such as an access speed to recorded information and an information transfer speed are required.

In response to such a demand, a hard disk device (hereinafter referred to as an HDD device) has been disclosed in Japanese Patent Laid-Open No. 55-84.
The use of an inductive type thin film magnetic head as disclosed in Japanese Patent Publication No. 020 is becoming mainstream. The thin-film magnetic head has a lower inductance than that of the previous bulk type head, and can perform recording and reproduction at a higher frequency.

However, as the disk diameter becomes smaller and the relative speed between the head and the recording medium decreases due to the miniaturization of the HDD device, a magnetic flux responsive reproducing head has been desired. In such a situation, a magnetoresistive effect element (MR element: MR element:
An MR reproducing head using a Magneteto-Resistance element has attracted attention. In practice, a composite MR head combined with the inductive thin film head has been put to practical use.

In recent years, in order to further improve the reproduction output, research and development of a composite MR head based on a giant magnetoresistance effect (GMR) using a thin film material exhibiting a greater magnetoresistance effect have been actively conducted.

[0006]

An important point for realizing a large-capacity storage is the reproduction sensitivity when reproducing stored data. In this respect, a composite MR by the MR effect is used.
The head is promising.

However, when the MR effect is used for the reproduction principle, a shield layer and a reproduction gap are required around the MR element. Further, it is necessary to make the MR film into a single magnetic domain. Further, a bias magnetic field is required to perform linear reproduction, and the head structure is considerably more complicated than the previous inductive head.

It goes without saying that as the structure of the magnetic head becomes more complicated, a more advanced manufacturing technique is required, and it becomes difficult to secure a high yield. The present invention has been made in view of the above problems, and provides a method of manufacturing a magnetic head having a relatively simple structure and a higher read sensitivity than a conventional inductive head for implementing a magnetic read method with a high read sensitivity. The purpose is to do.

[0009]

According to the method of manufacturing a magnetic head of the present invention, a step of forming a first soft magnetic layer having a predetermined pattern on a substrate made of an insulator; Forming a linear first conductor layer on the first soft magnetic layer so as to cross the first soft magnetic layer in a direction perpendicular to the magnetic field lines passing through the first soft magnetic layer; Forming a non-magnetic layer that forms a magnetic gap by forming a film into a predetermined shape on the first soft magnetic layer; and forming a second non-magnetic layer on the first soft magnetic layer by sandwiching the first conductive layer and the non-magnetic layer. Forming a soft magnetic layer, forming a dielectric layer having a predetermined dielectric constant on a surface of the substrate while exposing a predetermined portion of the first conductor layer to an outer surface, and forming the dielectric layer A second conductor connected to the first conductor layer and processed into a predetermined shape.
Forming a conductor layer, forming an electrode terminal connected to the first conductor layer and the second conductor layer, and forming a protective layer for protecting the electrode terminal; Removing the protective layer for exposing the electrode terminal to the surface from the protective layer.

According to the manufacturing method of the present invention, since the manufacturing process is simple, it is easy to secure a relatively high yield and excellent in mass productivity.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 The following embodiment relates to a method for manufacturing a magnetic head according to the present invention.

A magnetic head manufactured by the method of manufacturing a magnetic head according to the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view of the magnetic head. 2A is a cross-sectional view taken along the line II-II of FIG. 1, FIG. 2B is a front view of the magnetic head shown in FIG. 1, and FIG. FIG. 4 is an exploded perspective view showing the structure of details separated in a vertical direction for easy understanding. FIG. 4 is a vertically separate perspective view of an example of a magnetic head having a conductor layer 60 for applying a DC magnetic field, and FIG. 5 is a cross-sectional view of the magnetic head shown in FIG. 6A and 6B are diagrams for explaining a reproducing operation of the magnetic head of FIG. 1, and FIG. 6A is a diagram showing a positional relationship between the magnetic head and the recording medium, and FIG. 2) is an equivalent circuit diagram when the magnetic core of the magnetic head of FIG. 1 is an impedance element. FIGS. 7A and 7B show the reproduction voltage waveform of the magnetic head in the equivalent circuit of FIG. 6B.

In FIGS. 1 to 3, a substrate 100 includes:
For example, a conductive ceramic plate or a glass plate having a thickness of 2 mm is used. When a conductive substrate such as a conductive ceramic plate is used, an alumina film 51 having a thickness of about 20 μm is applied to the surface and mirror-finished. The upper core 1 formed on the surface of the alumina film 51 of the substrate 100 is a soft magnetic thin film made of a NiFe alloy and having a thickness of about 1.5 μm. The lower core 2 is also a soft magnetic thin film made of a NiFe alloy.

The conductor coil 3 is formed of a Cu thin film having a thickness of about 1 μm sandwiched between the upper core 1 and the lower core 2, and is also a ground terminal of a reproduction circuit system. Two conductor wires 4a,
One end of 4b is electrically connected to the two branched ends of the conductor coil 3, respectively. The other ends of the two conductor wires 4a and 4b are connected to electrode terminals 5 and 6, respectively. The material of the conductor wires 4a and 4b may be a Cu thin film or the like similar to the conductor coil 3, but is a high-resistance Ta thin film having a thickness of 0.5 μm in this embodiment. Conductor wires 4a, 4
It is important that b is adjusted in width and length so that the impedance value at a predetermined frequency becomes a desired value.

In order to provide a magnetic gap between the upper core 1 and the lower core 2, a magnetic gap portion 7 is formed of a non-magnetic film such as a Cu film having a thickness of about 0.3 μm. The arrow 8 is a vector representation of the magnetization (hereinafter, referred to as magnetization 8) recorded in the recording medium, and the magnetization 8 is perpendicular to the surface of the substrate 100. The arrow 9 indicates the direction of the magnetic flux passing through the upper core 1 and the lower core 2 due to the leakage magnetic field from the magnetization 8 when the magnetization 8 is near the magnetic gap 7. The conductor wire 10 has an end 10A connected to the conductor coil 3, but is arranged so as to cross over the upper core 1 while maintaining a predetermined interval via an alumina film 57 in other portions. . The electrode terminal 11
It is connected to the other end of the conductor wire 10. Electrode terminal 12
Is connected to the end of the conductor coil 3.

In FIG. 6B, the impedance element 29 is equivalent to the magnetic head shown in FIG. The carrier signal generator 22 is a signal source for supplying an AC constant current to the impedance element 29. A DC power supply 27 for applying a DC bias is connected in series, and is connected to the electrode terminals 5 and 6. . A DC bias magnetic field having a constant strength and direction is generated in the upper core 1 and the lower core 2 by the DC bias from the DC power supply 27. The resistance R represents the DC resistance of the conductor wires 4a, 4b.

FIGS. 4 and 5 are a perspective view and a sectional view, respectively, showing the components for generating a DC bias magnetic field in the upper core 1 and the lower core 2 by a method different from the above method. In both figures, a conductor film 60 is provided on an alumina film 51. Next, an alumina film 63 is provided as an insulator on the conductor film 60, and the lower core 2 is provided thereon. Both ends of the conductive film 60 are electrode terminals 61 and 62, respectively.
It is connected to the. The two electrode terminals 61 and 62 are connected to a DC power supply (not shown), and a DC current is supplied to generate a DC bias magnetic field in the upper core 1 and the lower core 2. As another method for generating a DC bias magnetic field, a permanent magnetic field may be arranged near the upper core 1 and the lower core 2. The electrode terminals 11 and 12 are terminals for outputting a voltage signal.

The signal reproduction by the magnetic head manufactured according to this embodiment will be described below. When the magnetic gap 7 of the magnetic head is on the magnetization 8 of the recording medium 26 as shown in FIG. 6A, the inside of the upper core 1 and the lower core 2 is shown in FIG. A magnetic flux indicated by an arrow 9 (hereinafter, referred to as a magnetic flux 9) passes through and is magnetized by the magnetic flux 9. Due to the magnetization, the magnetic permeability of the upper core 1 and the lower core 2 decreases. As a result, the effect that the impedance changes due to magnetism is equivalent to a state where the impedance of the impedance element 29 in FIG. At this time, since an AC constant current is flowing through the conductor wire 4, a back electromotive voltage proportional to the impedance is generated between the electrode terminals 11 and 12. That is, the output voltage value output from the electrode terminals 11 and 12 is proportional to the impedance value, that is, the magnetic permeability. The output voltage value is proportional to the amount of the magnetic flux 9 that flows in, that is, the strength of the magnetization 8.
So-called magnetic flux responsive reproduction is performed. In order to increase the output voltage value, the impedance is preferably as large as possible, and its magnetic field response is desired to be high. Therefore, it is preferable to supply a constant current having a frequency as high as possible within a range where the magnetic permeability of the magnetic core is high.

The magnetic head 200 and the magnetic recording medium 26 are in a positional relationship as shown in FIG. 6A. The operation when the magnetic gap is applied will be described with reference to FIG. (A) and (b) of FIG.
These figures show the output voltage V when no DC bias magnetic field is applied to the upper core 1 and the lower core 2 and when the DC bias magnetic field is applied. In FIGS. 7A and 7B, the left-hand diagrams each show the intensity of the magnetization 8 on the horizontal axis,
The value of the impedance Z of the impedance element 29 is shown on the vertical axis. The right-hand diagrams each show the waveform of the output voltage V.

As shown in FIG. 7A, when no DC bias magnetic field is applied, the change in the impedance Z of the head 200 is small and the change in the level of the output voltage V depends on the polarity of the magnetization 8. It does not depend on the magnitude of the magnetization 8 alone. As shown in FIG. 7B, when the DC bias magnetic field Hbias is applied, the impedance changes greatly and the magnitude of the impedance differs depending on the polarity of the magnetization 8.

As described above, by applying a DC bias magnetic field to the upper core 1 and the lower core 2, the polarity and the magnitude of the magnetization 8 can be more clearly output as shown in the right side of FIG. It is reflected on the voltage V. As described above, according to the present invention, a magnetic flux response type reproducing head can be obtained with a relatively simple configuration as compared with a conventional head using the MR effect.

FIG. 8 is a block diagram showing the configuration of a magnetic reproducing apparatus using the magnetic head described above. The magnetic head 200 is the same as the equivalent circuit shown in FIG. The high-frequency constant current source 22 to which the DC bias power supply 27 is connected in series is connected between the terminals 5 and 6, and supplies a constant-frequency high-frequency carrier current to the magnetic head 200. AM
The detector 46 is connected to the electrode terminals 11 and 12, and counter-emergence of an AM waveform generated in the MI element portion including the upper core 1, the lower core 2, and the magnetic gap 7 according to an impedance change caused by a leakage magnetic field of the external magnetization 8. The voltage V is detected and a reproduction voltage is output. The reproduction amplifier 47 is connected to the AM detector 4
6 for amplifying and outputting the reproduction voltage. The demodulation circuit 48 extracts a digital reproduction signal represented by, for example, 1 or 0 from the input reproduction voltage.

The operation of signal reproduction will be described below. First,
The electrodes 5 and 6 of the magnetic head 200 are supplied with a constant-frequency high-frequency current (for example, 700 MHz) from the high-frequency constant current source 22
Has been shed. In this state, if the external magnetization 8 is in the vicinity of the magnetic gap portion 7 as shown in FIG. 1, the MI element portion of the device whose impedance changes due to magnetism shown in FIG. , The impedance of the impedance element 29 changes. As shown in FIG. 7B, since an appropriate DC bias magnetic field is applied, the impedance greatly changes according to the strength and direction of the leakage magnetic field from the external magnetization 8.

In FIG. 8, since a high-frequency current having a constant amplitude flows as a carrier current in the impedance element 29 of the MI element section, the carrier is placed between the electrode terminals 11 and 12 at both ends of the impedance element 29 of the MI element section. A high frequency voltage at the frequency is generated.

The high-frequency voltage changes according to the change in the impedance of the impedance element 29, and an output voltage V having a waveform shown in the right part of FIG. 7B is obtained. This output voltage V is input to the AM detector 46 and subjected to AM detection to obtain an output signal indicated by a thicker bunched line in the waveform diagram on the right side of FIG. 7B. This output signal is amplified by the reproduction amplifier 47 and demodulated by the demodulation circuit 48 to become a reproduction output.

The method of manufacturing a magnetic head according to the present invention will be described below with reference to FIGS. First, a first manufacturing method of the present invention will be described with reference to FIG. 9A to 9J are cross-sectional views of the magnetic head, and the left side surface of each cross-sectional view corresponds to the surface K in FIG. The first manufacturing method includes the steps shown in FIGS. Thereafter, (A) to (J) of FIG.
Called. The material and thickness of each element in the steps A to J described in detail below are merely examples of each element, and are not limited to these. Selection is also within the scope of the present invention.

Step A: The substrate 100 is, for example, 2 mm thick.
An alumina film 51 is applied to an alumina / titanium carbide (AlTiC) substrate and mirror-finished. Step B: The entire surface of the alumina film 51 of the substrate 100 is covered with 1.5
A NiFe alloy layer 51 as a first soft magnetic layer having a thickness of μm is formed, and ion milling using a predetermined mask is performed.
The remaining portion of the NiFe alloy layer except for the portion to be the lower core 2 is removed.

Step C: Conductive wires 4 are formed by sputtering a Ta film and ion milling. In this process,
The thickness and width of the Ta film are set so that the impedance of the conductor wire 4 at 700 MHz becomes 50 ohms. Step D: The conductor coil 3 is formed by Cu sputtering and ion milling. The conductor coil 3 is a conductor wire 4
It is formed so that it may be connected to. The conductor coil 3 is also formed on a portion above the lower core 2.

Step E: Cu on the left area above the lower core 2
By sputtering and ion milling, a Cu film (0.3 μm thick) serving as the magnetic gap 7 is formed. The Cu film is also formed on the conductor coil 3, and the thickness of the conductor coil 3 increases accordingly. This part is a base part when forming the electrode terminals 5, 6, 11 and 12 in a later step. The film forming the magnetic gap 7 may be made of a material other than Cu as long as it is a nonmagnetic film. Step F: The upper core 1, which is the second soft magnetic layer, is formed on the lower core 2 and the Cu layer of the magnetic gap 7 by sputtering a NiFe alloy and ion milling.

Step G: A dielectric film 57 such as an alumina film is formed by sputtering and ion milling on the entire surface of each element of the substrate 100 except for the portions to be the electrode terminals 5, 6, 11 and 12. Step H: forming the conductor line 10 on the dielectric film 57, and
The electrode terminals 5, 6, 11 and 12 are formed on the Cu layer by sputtering of Cu and ion milling. The conductor wire 10 faces the conductor coil 3 on the lower core 2 formed in the step (4) via the dielectric film 57 to form a microstrip line structure.

Step I: A conductive layer is formed on the electrode terminals 5, 6, 11, and 12 by sputtering of Cu to increase the height of the electrode terminals 5, 6, 11, and 12. Next, an alumina film is formed as a protective film 18 on the entire surface of the substrate 100 including the components formed in steps A to H by sputtering. On the surface of the formed protective film 18, an uneven portion corresponding to the unevenness of each internal element is generated. Step J: The surface of the protective film 18 is cut and flattened by lapping processing, and ion milling is performed.
The hole 5A is formed by removing the protective film 18 at the portions of the electrode terminals 5, 6, 11, and 12, and the electrode terminals 5, 6, 11, and 12 are exposed.

Embodiment 2 Next, a second manufacturing method of the present invention will be described with reference to FIG. In the second manufacturing method, steps A and B are the same as those in the first manufacturing method of FIG.

Step C: Conductor coil 3 is formed on lower core 2 by sputtering of Cu and ion milling, and conductor coil 3 is formed on substrate 100. Step D: A Cu film (0.4 μm thick) serving as the magnetic gap 7 is formed on the lower core 2 by sputtering of Cu and ion milling.

Step E: The upper core 1 is formed on the lower core 2 and on the Cu film forming the magnetic gap 7 by sputtering and ion milling of a NiFe alloy. Step F: A conductor wire 4 for flowing a high-frequency carrier signal current is formed on the conductor coil 3 by sputtering and ion milling of the Ta film. The line width and film thickness of the conductor wire 4 are set such that the impedance between the electrode terminals 5 and 6 of the conductor wire through which a carrier current of a predetermined frequency flows becomes a predetermined value.

Step G: A dielectric film 5 made of a 3 μm-thick alumina film over the entire surface of each element on the substrate 100 except for the conductor wires 4.
7 is formed by sputtering and ion milling. The conductor wire 4 functions as an element of the microstrip line. Step H: A conductor wire 10 is formed on a portion of the dielectric film 57 opposite to the conductor coil 3 by Cu sputtering and ion milling. At the same time, the electrode terminals 5, 6, 1
A conductor portion 5B serving as a base for 1 and 12 is formed of a Cu film.

Step I: Electrode terminals 5, 6, 11, 1 on conductor portion 5B by sputtering or electroplating of Cu.
2 is formed to a height of 5 to 15 μm. In the case of sputtering, after providing a Cu film on the entire surface, portions of the electrode terminals 5, 6, 11, and 12 are formed by etching. In the case of the electroplating method, etching is performed after forming an electrode thin film for electroplating. In this embodiment, about 10 μm
A Cu film was formed by sputtering, and portions other than the electrode terminals 5, 6, 11, and 12 were removed by ion milling. Step J: An alumina film having a thickness of about 35 μm as a protective film is formed on the substrate 100 having each element, and the surface is flattened by lapping, and the electrode terminals 5, 6, 11, 12 are formed by ion milling. A portion of the alumina film is removed to expose the electrode terminals 5-12.

The soft magnetic layer may be, for example, a Co-based amorphous film or an Fe-based film. Also, various thin film manufacturing methods such as vapor deposition and sputter plating can be used. Further, needless to say, multilayering and adjustment of the anisotropic magnetic field for increasing the magnetic permeability at a high frequency may be performed as needed. Further, the material of the substrate, the material and the manufacturing method of the protective film are not limited to the present embodiment.

[0038]

According to the method of manufacturing a magnetic head of the present invention, the manufacturing process is simple, a relatively high yield is easily ensured, and the mass production is excellent.

[Brief description of the drawings]

FIG. 1 is a perspective view of a magnetic head manufactured by a manufacturing method according to a first embodiment of the present invention.

2A is a sectional view taken along the line II-II in FIG. 1; FIG. 2B is a front view of a plane K in FIG. 1;

FIG. 3 is a perspective view showing each element in FIG. 1 separated vertically in the drawing;

FIG. 4 is a perspective view showing each component of another configuration example of the magnetic head manufactured by the manufacturing method of the present invention, which is separated vertically in the drawing.

FIG. 5 is a sectional view taken along line VV of the magnetic head shown in FIG. 4;

FIG. 6A is a diagram showing a relative position between a magnetic head manufactured by the manufacturing method of the present invention and a magnetic recording medium. FIG. 6B is an equivalent circuit of a magnetic head manufactured by the manufacturing method of the present invention.

FIG. 7A is an explanatory view of a reproducing operation of a magnetic head manufactured by the manufacturing method of the present invention when there is no DC bias magnetic field; FIG. 7B is manufactured by the manufacturing method of the present invention when there is a DC bias magnetic field Illustration of reproducing operation of magnetic head

FIG. 8 is a block diagram of a magnetic reproducing apparatus using a magnetic head manufactured by the manufacturing method of the present invention.

FIG. 9 is a sectional view showing a method of manufacturing the first embodiment of the magnetic head according to the present invention.

FIG. 10 is a sectional view showing a manufacturing method of the second embodiment of the magnetic head according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper core 2 Lower core 3 Conductor coil 4, 4a, 4b Conductor wire 5, 6, 11, 12, 61, 62 Electrode terminal 7 Magnetic gap part 8 Magnetization 9 Magnetic flux in upper magnetic film 10 Conductor wire 100 Substrate 200 Magnetic head 26 Magnetic Disk 29 Impedance Element 22 High Frequency Constant Current Source 46 AM Detector 47 Reproduction Amplifier 48 Demodulation Circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akuro Kuroe 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A first pattern having a predetermined pattern on an insulating substrate.
Forming a soft magnetic layer; and forming a linear soft magnetic layer on the first soft magnetic layer so as to traverse the first soft magnetic layer in a direction orthogonal to a magnetic field line passing through the first soft magnetic layer. Forming a non-magnetic layer serving as a magnetic gap having a predetermined shape on the first soft magnetic layer; and forming the first magnetic layer on the first soft magnetic layer. Forming a second soft magnetic layer with a conductive layer and a non-magnetic layer interposed therebetween; and having a predetermined dielectric constant on the surface of the substrate while exposing a predetermined portion of the first conductive layer to an outer surface. Forming a dielectric layer; forming a second conductor layer formed on the dielectric layer, connected to a predetermined portion exposed to the outer surface of the first conductor layer, and processed into a predetermined shape; Forming electrode terminals connected to the first conductor layer and the second conductor layer Steps and, the steps of forming a protective layer for protecting the electrode terminals, the method of manufacturing the magnetic head, characterized in that a protective layer removal step for exposing the electrode terminals from the protective layer that.